The most powerful thing in the diablo universe is.......
A puddle of poison.
That is correct, a puddle of poison.
As gods and demons wage their war on each other, this lone puddle sits still and waits as mighty magic decimates anything around it. After the victor has been decided and the mighty warriors of legend congratulate each other, this little puddle sits and waits for the unsuspecting fool to touch it. Death is all that will come of touching this little puddle, and their god-like power can do naught, when faced with a all powerful puddle of poison.